SCBS079B − NOVEMBER 1991 − REVISED APRIL 1994
•
•
•
•
DW OR NT PACKAGE
(TOP VIEW)
State-of-the-Art BiCMOS Design
Significantly Reduces ICCZ
ESD Protection Exceeds 2000 V Per
MIL-STD-883C, Method 3015; Exceeds
200 V Using Machine Model (C = 200 pF,
R = 0)
3-State B Outputs Sink 48 mA or 64 mA
and Source 12 mA or 15 mA
Package Options Include Plastic
Small-Outline (DW) Packages and Standard
Plastic 300-mil DIPs (NT)
T/R
A1
A2
A3
A4
A5
VCC
A6
A7
A8
ODD/EVEN
ERR
description
The SN74BCT657 contains eight noninverting
transceivers with 3-state outputs and an 8-bit
parity generator/checker. It is intended for busoriented applications.
1
24
2
23
3
22
4
21
5
20
6
19
7
18
8
17
9
16
10
15
11
14
12
13
OE
B1
B2
B3
B4
GND
GND
B5
B6
B7
B8
PARITY
The transmit/receive (T/R) input determines the direction of the data flow through the bidirectional transceivers.
When T/R is high, data is transmitted from the A port to the B port. When T/R is low, data is received at the A port
from the B port.
When the output-enable (OE) input is high, both the A and B ports are placed in a high-impedance state
(disabled). The ODD/EVEN input allows the user to select between odd or even parity systems.
When transmitting from A port to B port (T/R high), PARITY is an output from the generator/checker. When
receiving from B port to A port (T/R low), PARITY is an input.
When transmitting (T/R high), the parity-select (ODD/EVEN) input is made high or low as appropriate. The A port
is then polled to determine the number of high bits. The PARITY output goes to the logic state determined by
the parity-select (ODD/EVEN) input and the number of high bits on A port. When ODD/EVEN is low (for even
parity) and the number of high bits on A port is odd, the PARITY will be high, transmitting even parity. If the
number of high bits on A port is even, the PARITY will be low, keeping even parity.
When in the receive mode (T/R low), the B port is polled to determine the number of high bits. If ODD/EVEN
is low (for even parity) and the number of highs on B port is as follows:
−
Odd and the PARITY input is high, then ERR will be high signifying no error.
−
Even and the PARITY input is high, then ERR will be low indicating an error.
The SN74BCT657 is characterized for operation from 0°C to 70°C.
Copyright 1994, Texas Instruments Incorporated
!"#$%! & '("")% $& ! *(+,'$%! -$%).
"!-('%& '!!"# %! &*)''$%!& *)" %/) %)"#& ! )0$& &%"(#)%&
&%$-$"- 1$""$%2. "!-('%! *"!')&&3 -!)& !% )')&&$",2 ',(-)
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• DALLAS, TEXAS 75265
• HOUSTON, TEXAS 77251−1443
POST OFFICE BOX 655303
POST OFFICE BOX 1443
2−1
SCBS079B − NOVEMBER 1991 − REVISED APRIL 1994
FUNCTION TABLE
NUMBER OF A OR B
INPUTS THAT ARE HIGH
0, 2, 4, 6, 8
1, 3, 5, 7
Don’t care
INPUTS
OUTPUTS
OE
T/R
ODD/EVEN
INPUT/OUTPUT
PARITY
ERR
OUTPUT MODE
L
H
H
H
Z
Transmit
L
H
L
L
Z
Transmit
L
L
H
H
H
Receive
L
L
H
L
L
Receive
L
L
L
H
L
Receive
L
L
L
L
H
Receive
L
H
H
L
Z
Transmit
L
H
L
H
Z
Transmit
L
L
H
H
L
Receive
L
L
H
L
H
Receive
L
L
L
H
H
Receive
L
L
L
L
L
Receive
H
X
X
Z
Z
Z
logic symbol†
OE
T/R
ODD/EVEN
A1
A2
A3
A4
A5
A6
A7
A8
24
1
11
2
3
G3
3 EN1/3G5 [REC]
3 EN2 [XMIT]
N4
1
23
1
2
Z11
22
4
21
5
20
6
17
8
16
9
15
10
14
11
12
13
14
15
16
17
18
2k
13
4, 2
B2
B3
B4
B5
B6
B7
B8
PARITY
5
4, 1
† This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
2−2
B1
•
POST OFFICE BOX 655303 DALLAS, TEXAS 75265
POST OFFICE BOX 1443 HOUSTON, TEXAS 77251−1443
•
12
ERR
SCBS079B − NOVEMBER 1991 − REVISED APRIL 1994
logic diagram (positive logic)
T/R
1
24
OE
2
A1
A2
A3
A4
A5
A6
A7
A8
ODD/EVEN
23
3
22
4
21
5
20
6
17
8
16
9
15
10
14
B1
B2
B3
B4
B5
B6
B7
B8
13
11
12
•
POST OFFICE BOX 655303 DALLAS, TEXAS 75265
POST OFFICE BOX 1443 HOUSTON, TEXAS 77251−1443
•
PARITY
ERR
2−3
SCBS079B − NOVEMBER 1991 − REVISED APRIL 1994
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)†
Supply voltage range, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −0.5 V to 7 V
Input voltage range, VI (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −0.5 V to 7 V
Voltage range applied to any output in the disabled or power-off state, VO . . . . . . . . . . . . . . . . −0.5 V to 5.5 V
Voltage range applied to any output in the high state, VO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −0.5 V to VCC
Input clamp current, IIK (VI < 0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −30 mA
Current into any output in the low state, IO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128 mA
Operating free-air temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to 70°C
Storage temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −65°C to 150°C
† Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
NOTE 1: The input and output negative-voltage ratings may be exceeded if the input and output clamp-current ratings are observed.
recommended operating conditions (see Note 2)
MIN
NOM
MAX
4.5
5
5.5
UNIT
VCC
VIH
Supply voltage
VIL
IIK
Low-level input voltage
0.8
V
Input clamp current
−18
mA
IOH
High-level output current
IOL
Low-level output current
High-level input voltage
2
A port
2−4
•
−15
A port
24
B port, PARITY, ERR
64
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POST OFFICE BOX 1443 HOUSTON, TEXAS 77251−1443
•
V
−3
B port, PARITY, ERR
TA
Operating free-air temperature
NOTE 2: Unused or floating pins (input or I/O) must be held high or low.
V
0
70
mA
mA
°C
SCBS079B − NOVEMBER 1991 − REVISED APRIL 1994
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
VIK
VCC = 4.5 V,
VCC = 4.5 V,
II = −18 mA
IOH = − 3 mA
VCC = 4.5 V,
VCC = 4.75 V,
IOH = −15 mA
IOH = − 3 mA
VCC = 4.5 V,
VCC = 4.5 V,
IOL = 24 mA
IOL = 64 mA
OE
VCC = 0,
VCC = 0,
VI = 7 V,
VI = 7 V,
ODD/EVEN
VCC = 0,
VI = 7 V
VCC = 5.5 V,
VI = 5.5 V
Any output
VOH
B port, PARITY, ERR
Any output
A port
VOL
B port, PARITY, ERR
T/R
II
TEST CONDITIONS
MIN
TYP†
2.4
3.3
2
3.1
T/R, OE
0.5
0.55
OE = 4.5 V
20
T/R = 4.5 V
20
20
200
VCC = 5.5 V,
20
VI = 2.7 V
IOZH
IOZL
ERR
ERR
ICCL
ICCH
ICCZ
Ci
Control input
−70
VCC = 5.5 V,
−20
VI = 0.5 V
B port, PARITY
µA
−20
−60
−200
−125
−300
VCC = 5.5 V,
VO = 0
VCC = 5.5 V,
VCC = 5.5 V,
VO = 2.7 V
VO = 0.5 V
−50
µA
VCC = 5.5 V,
VCC = 5.5 V,
Outputs open
90
mA
Outputs open
2
mA
VCC = 5.5 V,
VCC = 5 V,
Outputs open
1
mA
VCC = 5 V,
VO = 2.5 V or 0.5 V
VI = 2.5 V or 0.5 V
A port
Cio
µA
20
A port
B port, PARITY, ERR
µA
200
ODD/EVEN
IOS§
V
100
A or B port, PARITY
T/R, OE
V
0.42
ODD/EVEN
IIL‡
V
0.35
A or B port, PARITY
IIH‡
UNIT
−1.2
2.7
A port
B port, PARITY
MAX
50
6.5
mA
µA
pF
10
Co
ERR
VCC = 5 V,
VO = 2.5 V or 0.5 V
† All typical values are at VCC = 5 V, TA = 25°C.
‡ For I/O ports, the parameters IIH and IIL include the off-state output current.
§ Not more than one output should be tested at a time, and the duration of the test should not exceed one second.
•
POST OFFICE BOX 655303 DALLAS, TEXAS 75265
POST OFFICE BOX 1443 HOUSTON, TEXAS 77251−1443
•
14
10
pF
pF
2−5
SCBS079B − NOVEMBER 1991 − REVISED APRIL 1994
switching characteristics over recommended ranges of supply voltage and operating free-air
temperature, CL = 50 pF (unless otherwise noted) (see Note 3)
FROM
(INPUT)
TO
(OUTPUT)
tPLH
tPHL
A or B
B or A
tPLH
tPHL
A
PARITY
tPLH
tPHL
ODD/EVEN
PARITY, ERR
tPLH
tPHL
B
ERR
tPLH
tPHL
PARITY
ERR
tPZH
tPZL
OE
A, B, PARITY, or ERR
tPHZ
tPLZ
OE
A, B, PARITY, or ERR
PARAMETER
VCC = 5 V,
TA = 25°C
•
6
1.1
6.6
5.3
8.5
2
9
MAX
1.1
3.1
2
3
7.4
12.7
3
15.4
4.6
8.6
14.1
4.6
15.9
1.1
4.1
6.4
1.1
7.1
2.6
5.5
8.3
2.6
9
3.1
7.4
12.6
3.1
15.3
4.4
6.5
13.3
4.4
15.5
3.4
7.7
10.7
3.4
13.2
5.5
8.8
12
5.5
13.9
1.8
5.1
7.7
1.8
9.1
3.2
6.7
14.2
3.2
16.3
2.6
5.7
8
2.6
9.1
2
5
7.4
2
8
POST OFFICE BOX 655303 DALLAS, TEXAS 75265
POST OFFICE BOX 1443 HOUSTON, TEXAS 77251−1443
•
MAX
TYP
NOTE 3: Load circuits and voltage waveforms are shown in Section 1.
2−6
MIN
MIN
UNIT
ns
ns
ns
ns
ns
ns
ns
PACKAGE OPTION ADDENDUM
www.ti.com
18-Sep-2008
PACKAGING INFORMATION
Orderable Device
Status (1)
Package
Type
Package
Drawing
Pins Package Eco Plan (2)
Qty
Lead/Ball Finish
MSL Peak Temp (3)
SN74BCT657DW
OBSOLETE
SOIC
DW
24
TBD
Call TI
Call TI
SN74BCT657DWR
OBSOLETE
SOIC
DW
24
TBD
Call TI
Call TI
SN74BCT657NT
OBSOLETE
PDIP
NT
24
TBD
Call TI
Call TI
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in
a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check
http://www.ti.com/productcontent for the latest availability information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements
for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered
at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and
package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS
compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame
retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder
temperature.
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Addendum-Page 1
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